A Case of Monostotic Fibrous Dysplasia of the Frontal Sinus

Lee, Kyung Chul; Park, Sang Ouk; Lee, Yong Bae; Yang, Jae Young

Abstract

Fibrous dysplasia is a benign bone lesion characterized by the replacement of the normal substance of the interior of the bone by the fibro-osseous connective tissue exhibiting varying degree of osseous metaplasia histologically. In the head and neck, the most frequently involved area is the maxilla. We present 29 year-old male with diffuse swelling in the right frontal area, headache and nasal obstruction persisting for 2 years. Computed tomography scan of the paranasal sinus revealed irregular hyperdense mass arising from the right frontal sinus. The interfrontal septum was deviated to the left side by the mass. There was no evidence of invasion through and into the orbit and the cranial vault. Bilateral osteoplastic surgery of the frontal sinus was done. The mass was originated from the posterior wall of the right frontal sinus and expanded to the anterior wall. It's margin was poorly defined with adjacent normal osseous tissues, and it was removed by drilling and curettage. Left nasofrontal duct was well preserved, whereas right nasofrontal duct was obstructed by the mass. The pathologic finding consisted of an abundance of fibroblasts in interlacing bundles or whorls, connective tissue stroma of high vascularity, and islets of irregular trabeculae of new bone.